1. Field of the Invention
This invention relates to cargo carrying trailers and, more particularly, to a safety net assembly that is utilized to restrain cargo when the main cargo doors are opened.
2. Background Art
Cargo carrying trailers, such as on tractor-trailers, are made with a cubicle cargo storage space. Typically, cargo will be loaded progressively from front to rear through a rear opening that is selectively blocked by hinged doors.
Transportation of cargo is most efficient when all of the cargo space is utilized. Typically, the cargo will be loaded right up to the rear trailer opening. The cargo will be confined by the main cargo doors during vehicle movement. When cargo is to be unloaded at its destination, the process is initiated by opening the rear doors. Cargo that has shifted may be precariously situated and tend to tip out of the rear opening once the doors are opened. To avoid this condition, and reduce the likelihood of physical injury to personnel and/or damage to the cargo, it is known to restrain cargo by incorporating a flexible safety net.
Typically, the safety nets are made from flexible material that will span the entire area of the rear opening to confine any cargo, regardless of its stacked height. In a typical trailer construction, the height of the opening will be approximately 110″ above the floor. Thus, the safety net generally extends upwards from the floor that same distance.
Heretofore, safety net systems have been installed using different techniques and mechanisms. In one oft-used system, vertical tracks are mounted on the trailer side walls. A number of conventional fittings exist that can be locked onto the tracks to secure the net at spaced vertical locations, including a location adjacent the trailer roof.
Typically, the net will be made with at least two parts that are releasably joined at a vertical parting line that is at a mid-width location. Cooperating hook components are commonly used at spaced vertical locations on the net parts and are manually connected and disconnected by those securing and unloading the cargo. Ideally, to maintain the integrity of the safety net over its entire vertical extent, the cooperating hook components engage at or adjacent to the top of the safety net. To open the safety net, the user releases the hook components, whereupon the parts are separable and can be folded towards their respective sides. It is impractical for an individual of normal height to conveniently access the topmost hook components while standing on the trailer floor. The industry has come up with different mechanisms to facilitate access to these upper hook components.
As one example, a vertically adjustable, horizontal beam has been used as a safety net support. The beam has ends that cooperate with the tracks and is capable of being vertically adjusted to selectively raise and lower the top of the net. At the cargo destination, the entire beam can be lowered, while maintaining a horizontal orientation, to allow the net parts to be readily released from each other at the parting line by an individual standing on the trailer floor.
In this design, the beam is stored at the ceiling level, with the released safety net parts pushed oppositely to the sides of the trailer to be out of the path of cargo that is loaded or unloaded. One drawback with this design is that the beam for the net at all times extends down below the overhead structural beam at the rear opening. This reduces the effective cross-sectional area of the rear opening. The beam thus presents a possible obstruction to loading and unloading of cargo. The assignee herein currently offers such a product as its Ancra Lift-A-Deck® system.
As an alternative, the cross beam can be eliminated and the top corners of the safety net secured using lockable fittings offered by the assignee in another form of its Lift-A-Deck® system, as shown in assignee's U.S. Pat. No. 6,074,143. While the safety net is not shown in this patent, the vertical track and cooperating fittings guided vertically therein are usable, without the beam, to secure the safety net corners at selected heights potentially fully between the floor and ceiling as at the rear of the cargo space. Once the safety net parts are lowered and thereafter separated and shifted to their respective sides, the rear opening is unobstructed, as by a beam in the previously described design. However, this design requires the initial first step of simultaneous downward shifting of both upper corners of the safety net. Otherwise, if only one corner were to be lowered, the upper edge of the safety net would be required to tilt to a diagonal orientation. Since the width dimension of the upper edge of the net is substantially fixed, this diagonal orientation could not be achieved to an extent that would lower the uppermost hook components to a height that they might conveniently be reached.
In spite of an industry awareness of these problems, the problems have persisted since no commercially viable solutions are currently available.